1. Field of the Invention
The invention relates to a vehicle seat provided with a cushion and linear supporting members that support the cushion.
2. Description of Related Art
Japanese Patent Application Publication No. 2011-10748 (JP 2011-10748 A), for example, describes one such known vehicle seat that includes a seat cushion and a seat back. The seat back is a member that is tiltably connected to the seat cushion, and includes a generally rectangular frame member that forms a seat frame, a cushion, and a pair of supporting members. The pair of supporting members are both linear members that extend in a longitudinal direction of the frame member, and curve in a seat width direction at a center portion in the longitudinal direction. In other words, the frame member is formed in the shape of a crank.
Also, the cushion is a member (made of polyurethane foam) that elastically supports an occupant, and includes a bulging portion and a backing. The bulging portion is a semi-cylindrical (e.g., arc-shaped or the like in a sectional view) convex portion that bulges out at the center of the underside of the cushion and extends in the longitudinal direction of the cushion. Also, the backing is a planar-shaped member (spunbonded non-woven fabric) with less expandability than the cushion, and is arranged on the underside of the cushion.
In JP 2011-10748 A, the pair of supporting members are attached to the frame member and extend in the seat length direction. Also, when the cushion is arranged on the frame member, the cushion is supported by the pair of supporting members while the bulging portion is arranged between the pair of supporting members. With this kind of seat structure, for example, when the cushion is crushed by the load of an occupant, the seating comfort of the seat may decrease. Therefore, in JP 2011-10748 A, the pressing force received by the cushion is canceled out as much as possible by the repulsion force of the bulging portion, i.e., the contractile force of the hacking, such that the seating comfort of the seat is able to be well maintained.
However, in JP 2011-10748 A, the bulging portion is formed between the pair of supporting members. That is, the portion that the contractile force of the backing preferably acts on is formed on one portion of the cushion. Therefore, if the load of the occupant moves, as may occur when cornering, for example, the pressing force of the occupant is applied to another portion of the cushion (i.e., a location where the bulging portion is not formed), and as a result, the support performance of the cushion may be insufficient.